Tinken
Husqvarna
Pro Class
hi everyone just a few pointers on oils from an automotive engineer
1.car oils are NOT sutable for wet clutches found in motorbike engines additives in them will stop the plates gripping and soon burn it out and yes i have found out the hard way (even my childhood dt50 field bike with 3hp burnt its clutch using car oil!). and meny car oils can withstand gear shear here in europe meny cars run engine oils in the gear box some even like classic minis share the same oil for engine and gearbox (dry clutch)
2. multigrade oil ratings are stated as an equilvent to a mono grade's thickness @ the same temp so a 10w60 is the same as a 10 when cold and a 60 when hot this is the same no mater if its mineral or synthitic base. wider grades are almost always made from synthetic base oils as it is beyond the capabilitys of minrals.
you may get away with upping the w(cold grade) a bit in very hot climates or dropping the upper (hot) grade in very cold climates but oil grades are spec'ed by makers for a good reason and i would advise you to stick with them.
3. bikes like our huskeys or any other dirt bike need wide range oils as there is no thermostat or cooling fan in the cooling system so the engins running temp range is very wide compared to a road spec bike. it will take longer to heat up and may run hotter so the oil needs to be able to provide lubrication at all times.
hope this helps a few of you
btw im sticking with 10w60 in my bike even @ £50 for 4l here in the uk! probably cheaper in the long run than the repair bills
Many automotive engine oils today are suitable for use with wet clutches, with exception to most racing automotive oils which contain molybdenum disulphide and Teflon which cannot be used with wet clutches. In fact, many automotive engine oils offer an even higher rating than their motorcycle specific counterparts. Multigrade oil ratings are almost meaningless on today's engine oils, especially for motorcycles. Most companies do not follow proper standards for multigrade ratings, therefor the data sheets must be retrieved and centastroke values must be observed. Most modern Husqvarnas do come with cooling fans and thermostats. The oil in motorcycles does take quite a bit of time to warm to operating temperatures and this is why I recommend zero weight oils which do so much faster. Thinner oils are far superior in cooling and bearing separation than thicker oils. Because flow is inversely proportionate to pressure, and it is flow that lubricates, then minimum pressure must be maintained while maximizing our flow. The higher the flow, the higher the bearing separation, cooling and protection. It is because of this, heavier oils should not be used.
Unless your engine is greatly worn, you should never use higher grade oils than the manufacture's specification. However, you may use a thinner oil than manufacture's specify, if sufficient oil pressure can be maintained. This requires proper testing. For example; if your manufacture states you should use a 50 weight oil and you decide to use a 60, then your oil pressure will go up. But because your oil pressure went up, inversely your flow amount went down. Because oil pressure does not lubricate and flow does, you have decreased your engine's ability to lubricate and cool itself.
Husqvarnas typically have oil temperatures between 100 and 175°C. At 150°C, there is no difference between 40, 50 and 60 weights at this temperature, but these oils have a substantial impact on lubrication and cooling at the lower temperatures leading up to this temperature. Therefor it would be wise to use manufacture's specification or thinner.